Problem: Solve for $n$ : $-7 = 7 + n$
Solution: Subtract $7$ from both sides: $ \begin{eqnarray} \\ \hphantom{-7 {- 7}} &\hphantom{=}& \hphantom{n} \\ -7 &=& 7 + n \\ \\ {-7} && {-7} \\ \end{eqnarray} $ $ \begin{eqnarray} \\ -7 {- 7} &=& n \\ \end{eqnarray} $ Simplify. $ n = -14$